Roos? CM or BR?

I ordered 6 CM and 6 BR pullets from MacMurray, hatched FEB.5. I can't tell them apart as they don't distinctively have pink or yellow legs. Three chicks died very young. So I have 3-6 of each breed. Meanwhile, there are 2 that seem like roos to me. They are lighter, taller, braver than the others, have no black on legs and have very distinctive white stripes. the rest have mostly black with blurry white lines. They are the central birds in photos 1 and 2. Photo 3 shows some of the others.

Questions:

Are the birds in photos 1 and 2 roos? Or are chicks of one of these breeds lighter?

The taller one in pic 1 looks like a roo for sure! The comb is already very large. Not sure on which breed, I don't have either of those but that looks exactly like our Black sex link roos when they were younger. Usually you can send photos via email to the hatcheries and they can help identify them.

The bird in the top photo with the great profile shot and big comb is definitely a roo, and I lay odds a Cuckoo Marans (they show very early).

It's hard to tell at this stage for me as they don't have enough patterning yet to see if they are clear bars (Barred Rocks) or messier "dotty" zigs (Marans). In a couple of weeks you'll know which are which as the Barreds will all look clearly barred, crisp barred lines...the males will be lighter than the females (double barred), but definitely still crisp bars. Marans look sort of mussy zig zags.

I have noticed a difference in the body type between the Marans and the Barred Rocks. Barreds are lower to the ground and more refined. Marans tend to be heavier boned and more upright, and the roo's often show very early..from my recent experience and from others relaying theirs as well.

I'll post a photo of my Black Copper Marans chicks at 4 weeks, and you'll see both the 2 females and the one male roo (obvious as to who) generally have a more upright body shape.